igneous
Quartz-bearing granite or granitic pegmatite
Coarse felsic intrusive rock, chiefly quartz (SiO₂), feldspar, and mica; exact identification requires testing
AI-generated identification · may be incorrectGray-white, coarse granular texture with glassy/translucent quartz and pale feldspar; quartz is Mohs 7 with vitreous luster and no cleavage, while feldspar is Mohs 6–6.5 with two cleavages. Specific gravity is typically about 2.6–2.7.
Identified More igneous →
Explore Quartz-bearing granite or granitic pegmatite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Gray-white, coarse granular texture with glassy/translucent quartz and pale feldspar; quartz is Mohs 7 with vitreous luster and no cleavage, while feldspar is Mohs 6–6.5 with two cleavages. Specific gravity is typically about 2.6–2.7.
Formation & geological history
Formed by slow cooling of silica-rich magma deep underground, allowing large interlocking crystals to grow; likely Precambrian to younger, depending on locality.
Uses & applications
Commonly used as crushed stone, aggregate, dimension stone, and occasionally decorative material; ordinary hand specimens have little jewelry value.
Geological facts
The granular interlocking texture distinguishes granite from volcanic rhyolite, which is usually fine-grained. Dark patches may represent biotite or weathered mafic minerals.
Field identification & locations
Look for visible quartz, blocky feldspar, and shiny black or brown mica; a steel nail generally will not scratch quartz, but can scratch softer feldspar. Common worldwide in continental mountain belts and exposed plutons.
